The present invention relates to the transmission of input from two members into a unidirectional output. Further, the output can be reversed. Further, certain embodiments of the invention relate to power transmission into an output member.
In certain transmission arrangements, such as hand tools, it is common to provide an input member which drives in one direction and ratchets free in a second direction. This ratcheting is wasted motion, as it is not converted into drive of the output member. Further, other arrangements are known which include oscillatory input to provide unidirectional output. However, in these arrangements, all of the input is interdependent. When an input member is driven, all other parts of the input are also automatically moved in some way. These arrangements do not provide independent input elements. An example of a patent providing interdependent input is Goldmann U.S. Pat. No. 778,855.
According to specific embodiments, including the motor, it is known to include a motor in such devices as motor driven screwdrivers. However, in these arrangements, there are only three settings. One setting drives the output in a clockwise direction. Another setting drives the output in a counterclockwise direction. The final setting locks the output so that it can be manually driven in either direction directly. Because of the arrangement of the motor drive, these known devices do not provide for a setting which allows drive of an output in only one direction when the motor is not operable, with free ratcheting in the other direction.
It is an object of the present invention to provide a transmission which produces unidirectional output through two input members such that there is no lost motion on a return swing of one of the input members.
It is another object of the present invention to provide such a transmission with reversibility such that the output member can be reversed without changing the relative movement of the input members.
It is still a further object to provide a transmission for use with a motor which is also capable of unidirectional drive for oscillatory motion.
These objects are achieved by providing first and second input members which are independently operable from one another. Engaging elements are provided for directly engaging between the input members and an output member, thereby transferring rotation of the input members to the output members. A reversing element is provided which has two positions. In a first position, the reversing member provides engagement between the first and second input members when these input members are rotated in a first direction and allows free rotation of the input members relative to the output member in a second direction. The reversing members' second position reverses the direction of output by engaging the input members when rotated in the second direction and allows free rotation in the first direction.
According to advantageous features of certain preferred embodiments of the invention, a motor element is provided for automatically driving at least one of the input members. In certain preferred embodiments, the motor element is arranged such that it can drive the output member in a first direction and allows ratcheting or free motion if a handle is moved opposite to the first direction. Thus, the motor element does not lock up the output member and ratcheting action is permitted. In this embodiment, the output member can be driven manually by a handle and/or automatically by a motor element in a given direction and ratcheting is provided when the handle is moved opposite to the direction of the desired output. This is especially advantageous such that for low torque operation, the motor element can exclusively drive the output and/or high torque operations which may not be suitable for small battery operated motors, normal manual ratchet wrench operation can be provided without locking up the motor with the output member.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.